The media have widely reported on a recent study showing that Targretin, an FDA approved drug for treating skin cancer, was effective in clearing amyloid plaques from the brains of mice. Given that the presence of amyloid in the brain is a pathological hallmark of Alzheimer's disease, many were optimistic about the potential for a new treatment.

Alas, the scientific process of duplicating results before accepting them as valid, is an important step in generating new knowledge. In this case, three attempts to duplicate the original findings have all failed. That is to say, no other lab has been able to show a reduction of amyloid in the brains of mice treated with Targretin.

The original study with the positive result was conducted at Case Western University Medical Center and published in the journal Science. In its latest edition, the same journal published a technical comment describing the negative results in three other labs.